<template>
  <div class="component-upload-image">
    <el-upload multiple :action="uploadImgUrl" list-type="picture-card" :on-success="handleUploadSuccess"
      :before-upload="handleBeforeUpload" :limit="limit" :on-error="handleUploadError" :on-exceed="handleExceed"
      ref="imageUpload" :on-remove="handleDelete" :show-file-list="true" :headers="headers" :file-list="fileList"
      :on-preview="handlePictureCardPreview" :class="{ hide: this.fileList.length >= this.limit }">
      <i class="el-icon-plus"></i>
    </el-upload>

    <!-- 上传提示 -->
    <div class="el-upload__tip" slot="tip" v-if="showTip">
      请上传
      <template v-if="fileSize"> 大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b> </template>
      <template v-if="fileType"> 格式为 <b style="color: #f56c6c">{{ fileType.join("/") }}</b> </template>
      的文件
    </div>

    <el-dialog :visible.sync="dialogVisible" title="预览" width="800" append-to-body>
      <img :src="dialogImageUrl" style="display: block; max-width: 100%; margin: 0 auto" />
    </el-dialog>
  </div>
</template>

<script>
import { getToken } from "@/utils/auth";

export default {
  props: {
    value: [String, Object, Array],
    // 图片数量限制
    limit: {
      type: Number,
      default: 5,
    },
    // 大小限制(MB)
    fileSize: {
      type: Number,
      default: 0.5,
    },
    // 文件类型, 例如['png', 'jpg', 'jpeg']
    fileType: {
      type: Array,
      default: () => ["png", "jpg", "jpeg"],
    },
    // 是否显示提示
    isShowTip: {
      type: Boolean,
      default: true
    }
  },
  data() {
    return {
      number: 0,
      uploadList: [],
      dialogImageUrl: "",
      dialogVisible: false,
      hideUpload: false,
      baseUrl: process.env.VUE_APP_BASE_API,
      uploadImgUrl: process.env.VUE_APP_BASE_API + "/common/upload", // 上传的图片服务器地址
      headers: {
        Authorization: "Bearer " + getToken(),
      },
      fileList: []
    };
  },
  watch: {
    value: {
      handler(val) {
        if (val) {
          // 首先将值转为数组
          const list = Array.isArray(val) ? val : this.value.split(',');
          // 然后将数组转为对象数组
          this.fileList = list.map(item => {
            if (typeof item === "string") {
              if (item.indexOf(this.baseUrl) === -1) {
                item = { name: this.baseUrl + item, url: this.baseUrl + item };
              } else {
                item = { name: item, url: item };
              }
            }
            return item;
          });
        } else {
          this.fileList = [];
          return [];
        }
      },
      deep: true,
      immediate: true
    }
  },
  computed: {
    // 是否显示提示
    showTip() {
      return this.isShowTip && (this.fileType || this.fileSize);
    },
  },
  methods: {
    compress(inputFile, callback) {
      const self = this;
      const reader = new FileReader();
      reader.readAsDataURL(inputFile);
      reader.onload = function (e) {
        //防止照片文件过大无法上传， 通过以下代码重新创建一个固定宽高的图片再上传
        var image = new Image();
        image.src = this.result; //转化为base64字符串
        self.base64img = image.src
        image.onload = function () {

          var expectWidth = this.naturalWidth;
          var expectHeight = this.naturalHeight;
          if (this.naturalWidth > this.naturalHeight && this.naturalWidth > 600) {
            expectWidth = 600;
            expectHeight = (expectWidth * this.naturalHeight) / this.naturalWidth;
          } else if (this.naturalHeight > this.naturalWidth && this.naturalHeight > 450) {
            expectHeight = 450;
            expectWidth = (expectHeight * this.naturalWidth) / this.naturalHeight;
          }
          var canvas = document.createElement('canvas');
          var ctx = canvas.getContext('2d');
          canvas.width = expectWidth;
          canvas.height = expectHeight;
          ctx.drawImage(this, 0, 0, expectWidth, expectHeight);
          var dataurl = canvas.toDataURL('image/jpeg', 1);
          // 0到1之间的取值，主要用来选定图片的质量，默认值是0.92，超出    
          //范围也会选择默认值。
          // callback(dataurl)
          var arr = dataurl.split(','),
            mime = arr[0].match(/:(.*?);/)[1],
            bstr = atob(arr[1]),
            n = bstr.length,
            u8arr = new Uint8Array(n);
          while (n--) {
            u8arr[n] = bstr.charCodeAt(n);
          }
          //修改上传文件名，重新整理进fileList
          var newf = new File([u8arr], inputFile.name, {
            type: mime
          });
          newf.uid = inputFile.uid
          callback(newf)
        };
      };
    },

    // 上传前loading加载
    handleBeforeUpload(file) {
      this.$modal.loading();
      let isImg = false;

      //console.log(file, "未压缩的图片file")
      let _this = this;

      if (_this.fileType.length) {
        let fileExtension = "";
        if (file.name.lastIndexOf(".") > -1) {
          fileExtension = file.name.slice(file.name.lastIndexOf(".") + 1);
        }
        isImg = _this.fileType.some(type => {
          if (file.type.indexOf(type) > -1) return true;
          if (fileExtension && fileExtension.indexOf(type) > -1) return true;
          return false;
        });
      } else {
        isImg = file.type.indexOf("image") > -1;
      }

      if (!isImg) {
        _this.$modal.msgError(`文件格式不正确, 请上传${_this.fileType.join("/")}图片格式文件!`);
        _this.$emit("handleError",`文件格式不正确, 请上传${_this.fileType.join("/")}图片格式文件!`);
        _this.$modal.closeLoading();

        return false;
      }
      if (_this.fileSize) {
        const isLt = file.size / 1024 / 1024 < _this.fileSize;
        if (!isLt) {
          
          _this.$modal.msgError(`上传图片大小不能超过 ${_this.fileSize} MB!`);
          _this.$emit("handleError",`上传图片大小不能超过 ${_this.fileSize} MB!`);
          _this.$modal.closeLoading();

          return _this;
        }
      }

      return new Promise((resolve, reject) => {
        _this.$modal.loading("正在上传图片，请稍候...");
        _this.$modal.closeLoading();

        _this.number++;

        resolve(file)

        // _this.compress(file,
        //   (newfileex) => {

        //     file = newfileex;
        //     console.log(file, "22222")


        //     console.log('newFile', newfileex)
        //     resolve(newfileex)
        //   })
      })
    },
    // 文件个数超出
    handleExceed() {
      this.$modal.msgError(`上传文件数量不能超过 ${this.limit} 个!`);
       _this.$emit("handleError",`上传文件数量不能超过 ${this.limit} 个!`);
    },
    // 上传成功回调
    handleUploadSuccess(res, file) {
      if (res.code === 200) {
        this.uploadList.push({ name: res.fileName, url: res.fileName });
        this.uploadedSuccessfully();
      } else {
        this.number--;
        this.$modal.closeLoading();
        this.$modal.msgError(res.msg);
        _this.$emit("handleError",res.msg);
        this.$refs.imageUpload.handleRemove(file);
        this.uploadedSuccessfully();
      }
    },
    // 删除图片
    handleDelete(file) {
      const findex = this.fileList.map(f => f.name).indexOf(file.name);
      if (findex > -1) {
        this.fileList.splice(findex, 1);
        this.$emit("input", this.listToString(this.fileList));
      }
    },
    // 上传失败
    handleUploadError() {
      this.$modal.msgError("上传图片失败，请重试");
      _this.$emit("handleError","上传图片失败，请重试");

      this.$modal.closeLoading();
    },
    // 上传结束处理
    uploadedSuccessfully() {
      if (this.number > 0 && this.uploadList.length === this.number) {
        this.fileList = this.fileList.concat(this.uploadList);
        this.uploadList = [];
        this.number = 0;
        this.$emit("input", this.listToString(this.fileList));
        this.$modal.closeLoading();
      }
    },
    // 预览
    handlePictureCardPreview(file) {
      this.dialogImageUrl = file.url;
      this.dialogVisible = true;
    },
    // 对象转成指定字符串分隔
    listToString(list, separator) {
      let strs = "";
      separator = separator || ",";
      for (let i in list) {
        if (list[i].url) {
          strs += list[i].url.replace(this.baseUrl, "") + separator;
        }
      }
      return strs != '' ? strs.substr(0, strs.length - 1) : '';
    }
  }
};
</script>
<style scoped lang="scss">
// .el-upload--picture-card 控制加号部分
::v-deep.hide .el-upload--picture-card {
  display: none;
}

// 去掉动画效果
::v-deep .el-list-enter-active,
::v-deep .el-list-leave-active {
  transition: all 0s;
}

::v-deep .el-list-enter,
.el-list-leave-active {
  opacity: 0;
  transform: translateY(0);
}
</style>

